This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our specific aims are: To measure Muscle Blood Flow (MBF) and Skin Blood Flow (SBF) microcirculatory increases in the leg caused by mild external compression in healthy subjects and patients with Chronic Venous Insufficiency (CVI). To measure muscle oxygenation changes in the leg caused by mild external compression in healthy subjects and patients with Chronic Venous Insufficiency (CVI). To optimize pressures of Continuous Compression to induce maximum microcirculatory blood flow in healthy subjects and patients with CVI. To optimize compression pressures, duration, and frequency of Intermittent Pneumatic Compression (IPC) to induce maximum microcirculatory blood flow in healthy subjects and patients with CVI.